The present invention relates generally to hydraulic actuators, and more specifically, to a directional converter for use with a hydraulic actuator.
Frame racks are typically used to straighten the frame of an automotive vehicle after a collision. A frame rack has a deck onto which the vehicle is placed. A number of towers are positioned around the frame rack. The towers have a chain connected thereto that is coupled to a ram. The chains are connected to the frame of the vehicle and the tower is used to pull the chain toward the tower. Typically, the chains are connected to the vehicle so that the vehicle frame is pulled out in the same direction of impact. When the pulling of the frame begins, it is often necessary to adjust the direction of pulling so the pulling force remains in the direction of impact. Oftentimes, this requires the tension to be released from the vehicle, the tower position to be adjusted, and tension placed on the vehicle frame in a slightly different direction. This, however, is a time consuming process and thus increases the expense of the collision repair.
Many frame racks employ a single directional pump. This allows the frame to be pulled in a single direction. Many times both pushing and pulling is desired.
It would therefore be desirable to provide a system for allowing flexibility in the frame straightening process.
It is therefore one object of the invention to provide a directional converter for a hydraulic actuator that can be easily maneuvered and placed on various positions of a frame rack. The directional converter allows the one-directional fluid flow from a pump to be controlled and reversed. This control allows a hydraulic actuator to be easily positioned and moved to provide pushing and pulling capabilities.
In one aspect of the invention, a directional converter for use with a pump and a hydraulic actuator comprises a housing having a plurality of fluid passages therethrough. The plurality of fluid passages terminates in a pump outlet port, a pump inlet port, a first actuator port, and a second actuator port. A plurality of valves is disposed within the plurality of fluid passages. The plurality of valves has a first position and a second position. In a first position, a fluid flow direction at the first actuator port is into the housing from the actuator, and a fluid flow direction at the second ram port is out of the housing. When the switches are in a second position the first fluid flow direction is out of the housing and the second fluid flow direction is into the housing. The valve positions are preferably set so that two of the valves are open and two of the valves are closed when in operation.
In a further aspect of the invention, a hydraulic system comprises a pump having a fluid feed and a fluid release. Hydraulic actuator has an advance port and a retract port. A directional converter is fluidically coupled between the pump and the hydraulic actuator. The converter has a housing having a plurality of fluid passages therethrough. The plurality of fluid passages terminates in a pump outlet port, a pump inlet port, a first actuator port, and a second actuator port. The pump outlet port is coupled to the fluid release of the pump. The pump inlet port is fluidically coupled to the fluid feed of the pump. The first actuator port and second actuator port are respectively coupled to the advance port and the retract port. A plurality of valves is disposed within the fluid passages. The plurality of valves have a first position and a second position. In the first position, a fluid flow direction at the first actuator port is into the housing from the actuator and a second fluid direction and a second actuator port is out of the housing. When the switches are in a second position the fluid flow direction is out of the housing at the second actuator port.
In a further aspect of the invention, a method of operating a directional converter includes the steps of: providing a pump coupled to an actuator through a converter; actuating a plurality of switches in a first position and a second position; in a first position, flowing hydraulic fluid a first fluid flow direction at a first actuator port into a housing from the actuator and a second fluid flow direction at the second actuator port out of the housing; and when the switches are in a second position, flowing fluid in the first fluid flow direction at the first actuator port out of said housing and second fluid flow direction at said second actuator port into said housing.
One advantage of the invention is that the system may be adapted to use the single direction pump typically found on a frame rack. The system, however, is not limited to the use of the pump on frame rack and may use a stand-alone pump. Likewise, various types of hydraulic actuators may be used with the present invention. The present invention is suitable for various types of actuators in which a reverse flow is useful.
Other advantages and features of the present invention will become apparent when viewed in light of the detailed description of the preferred embodiment when taken in conjunction with the attached drawings and appended claims.